This invention relates generally to devices for separating and removing particulates from the air such as dirt, dust, rain, and snow, before they enter the air stream of an engine, air compressor, or similar apparatus.
Air filters are conventionally used to filter air being drawn into an internal combustion engine. Air precleaners are devices used to remove dust, dirt, sand, rain, snow, and other airborne particulates in the intake air prior to the flow of air through the filter. Precleaners promote more efficient combustion and longer engine and filter life. The efficiency of the precleaner is determined by the percentage of particulates that are removed from the intake air by the precleaner. The more efficient the precleaner, the lesser the amount of particulates that must be removed by the air filter.
The precleaners of the prior art have various configurations that are employed as a means of removing the particulates from the air. Examples of precleaners or particle separators are shown in U.S. Pat. Nos. 2,193,479; 2,304,778; 2,417,130; 2,973,830; 3,552,102; 3,670,480; 3,740,932; 3,791,112; 3,973,937; 4,138,761; 4,197,102; 4,547,207; 5,022,903; 5,449,391; and 5,505,756.
Although such precleaners may adequately perform with respect to particulate removal, this is sometimes accomplished at the expense of a reduced air flow, i.e., the precleaner itself may become an air restriction. There is generally a trade-off between efficiency of particulate renewal and air intake restriction.
Precleaners for use with motor vehicles are typically mounted on a stack that extends above the hood of a vehicle. The air filter is usually mounted under the hood near the carburetor or intake manifold. Attempts have been made to mount the precleaner and filter adjacent to one another utilizing precleaners with conventional bottom air intake, thus requiring that the precleaner still be spaced a distance from the filter canister which is sufficient to permit free flow of air to the precleaner.
The intake air cleaning apparatus in accordance with the invention provides highly efficient cleaning of intake air for internal combustion engines and the like with low air flow restriction. The apparatus of the invention provides removal and discharge of particulates from the intake air as well as thorough air filtering in a compact unit that is well adapted to be mounted within the engine compartment of a vehicle. Because of the compactness of the apparatus, it does not occupy significantly greater space than a conventional air filter unit. The apparatus is formed so that it can be readily disassembled in part to allow access to filters for cleaning and replacement.
The intake air cleaning apparatus in accordance with the invention preferably includes a filter canister and a filter mounted therein. The filter canister has an inlet end with an air inlet opening and an outlet end with an air outlet opening. A filter is mounted in the canister to filter the air flowing from the inlet opening to the outlet opening. A hood is mounted to the filter canister at the inlet end thereof and has a discharge port for discharging particulates. The hood and inlet end of the filter canister define an air space. A circumferential gap is defined between the hood and the filter canister. A series of vanes are mounted in the gap at an angle between radial and tangential to define channels between them through which air is directed into the air space. A rotor assembly is mounted within the air space to fling particulates toward the hood for expulsion through the discharge port. Because the air intake is through the gap between the hood and the inlet end of the filter canister, rather than through the bottom of the hood as in conventional air precleaners, the hood can be mounted to the filter canister to provide a compact and rugged one-piece unit.
The filter canister preferably has a cylindrical outer wall, an inlet end wall defining the inlet end with the inlet opening therein, and an outlet end wall defining the outlet end with the outlet air opening therein. The filter is preferably cylindrical and has a closed top end and an open bottom end which is in communication with the outlet opening of the canister. An outermost surface of the cylindrical filter is spaced inwardly from the cylindrical outer wall of the canister to define an air space that is in communication with the inlet opening of the canister such that air flowing into the inlet opening of the canister flows into the air space and then through the cylindrical filter to the outlet opening of the canister. The cylindrical wall of the canister is preferably formed in two separable parts comprising an upper section and a lower section. Clamps mounted to one of the sections provide a means for releasably joining the upper section and the lower section together. When the filter is to be cleaned or replaced, the operator can readily open the clamps to allow the top portion of the canister with the hood mounted thereto to be separated from the bottom portion of the canister, exposing the filter. When the filter has been cleaned or replaced, the top section of the canister with the hood attached thereto can be assembled back into place on the bottom section of the canister and the clamps manipulated to hold the two sections of the canister tightly together.
The filter preferably is formed into two parts, including an outer cylindrical coarse filter having an outer surface and an inner surface, and a cylindrical inner filter having an outer surface with a diameter smaller than the inner surface of the outer filter. The cylindrical interior of the inner filter is in communication with the outlet opening of the canister. The outer cylindrical filter has a closed top end and an open bottom end which is engaged with the outlet wall of the canister to provide an air tight seal.
The intake air cleaning apparatus of the invention thus carries out in a single unit the functions conventionally performed by a separate air precleaner and air filter. The apparatus is particularly adapted to be mounted within the engine compartment of a vehicle. If desired, the apparatus may also be mounted as a unit outside the engine compartment of a vehicle, e.g., at the top of the stack pipe. In use, air is drawn in through the gap and between the vanes and is directed upwardly within the hood to propel the rotor to fling particulates through the discharge port in the hood. The precleaning of the particulates from the air reduces the volume of material that must be cleaned from the air by the filters, extending filter life. The intake air then passes through the inlet opening of the filter canister and into the air space between the cylindrical canister wall and the outer cylindrical surface of the outer coarse filter. The outer cylindrical filter may have a large aspect ratioxe2x80x94the ratio of height to diameterxe2x80x94providing a large area through which air can be drawn into the outer filter, thereby minimizing the air flow restriction associated with the passage of air through the outer filter. Similarly, the inner filter preferably has a large aspect ratio and a relatively large area over which air may be drawn in through the material of the inner filter and thence to the outlet opening of the canister. The use of both an outer filter and an inner filter allows different materials to be used in the inner filter and outer filter, with the outer filter being formed of a filter material which can readily collect relatively larger dirt and dust particles, moisture, oils, and so forth, to prevent such materials from passing to the inner filter, which may be formed of a material which provides finer filtering but would otherwise be more easily clogged by the material that has been removed by the outer filter.
Further objects, features and advantages of the invention will be apparent from the following detailed description which taken in conjunction with the accompanying drawings.